The writer/-director/producer behind a string of modern comedic blockbusters – including “The 40-Year Old Virigin,” “Superbad,” “Bridesmaids” and HBO’s “Girls” – reunites several of his familiar troupe of players – including real-life wife Leslie Mann and friend Paul Rudd, reprising their “Knocked Up” characters – for “This Is 40,” an on screen examination of his own aging anxieties.

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Apatow, Mann and Rudd joined with co-stars Albert Brooks and Megan Fox to dig ever deeper into mining middle age for movie laughs, and the perils of playing an improvised scene opposite the likes of Melissa McCarthy.

On aging not-so-gracefully:

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Judd Apatow: I claim that I haven’t had a nervous breakdown from turning 40, and that it was more 30, but the evidence of the two movies [“This Is 40” and “The 40-Year Old Virgin”] prove I’m full of it.

Leslie Mann: I think every day is different. Some days, I feel fine, and other days I feel like crying all day. I have lunches with my girlfriends, who just turned 40, and some of those lunches, we’re crying and screaming about our husbands, saying we want to leave them and run away. And then, other lunches, we’re fine and love our husbands and are happy with our lives. So I’m not sure. I don’t have any answers. I keep asking women who are a little bit older, “When is this going to pass?” and they’re like, “It doesn’t pass – it just gets worse.”

Paul Rudd: I remember, as a kid, my dad always told me, “Getting older beats the alternative.” Although now my father actually is the alternative, so I don’t know what he would say. He’s dead. He’s completely dead. That just livened everything up, didn’t it?

Albert Brooks: When I was very young, I started to make friends with much, much older people. When I was 20, my friends were 50, so I never really went through 40. I would watch them die and always feel younger. You make friends with older people and you always feel young, no matter what. On my 40th birthday, I was in hospice with a 92-year-old buddy. [Pause] That’s a lie.

Megan Fox: I married my husband, who’s 13 years older, so I’ll always be a trophy wife for him.

On handling Apatow’s trademark move, allowing actors to improvise their own dialogue:

Fox: We had to do all of this improv, which I am not familiar with at all. I was so scared s***less then, but I got over it. But there was that one day on set where I memorized the wrong scene. I didn’t know my dialogue and I was so scared that I didn’t know it that I started doing all these crazy things in the scene – which maybe worked. But I was so scared that day.

Apatow: The best line that Albert made up on the fly, which is the fun part of loosening it up on the end after getting the scripted version and then starting to play, was that we know we wanted Albert’s character to be excited by how much money John Lithgow makes, and the wording is one of my favorite wordings of the movie: “So every time I don’t see a hunchback, you make money.” Albert would actually email me jokes the night before which would top many of my jokes, so I would be very happy.

Mann: Melissa McCarthy was the hardest one to get through. That was impossible. I’ve never experienced that. Maybe one time, I’ll crack up, and then I can hold it together, from then on. But with her, it was hours. We could not keep a straight face. Finally, we just gave up. Judd was using more than one camera, so we could just laugh and the crew were all laughing – It was ridiculous. She’s just the funniest person, ever.

Rudd: I’ve seen people in tears before, but that was something otherworldly. People were leaving the room. Crew had to leave. It was impossible. And she just kept her composure through all of it.

Apatow: I’ve never seen anything like that, other than Chris Farley. If he looked you in the eye, if you had to do anything with him, you would bust up. There’s a certain madness to some people that you just had to stare at their foreheads.

Mann: That didn’t work either. Nothing worked.

On how their offscreen lives influence their onscreen comedy:

Apatow: Leslie and I talk about the movie for years together, and that’s where a lot of the scene ideas come from, and it’s a little bit of a coded conversation where we’re really debating our own problems with each other. So Leslie can complain about Pete, but not about me. I’ll say “Don’t you think we should have a scene where we really point out how controlling Debbie is?” and she’ll say “Yeah – but maybe there should be a moment where Pete points out that he’s really a dick.” And we go back and forth like that, kind of subtly talking to each other, and then at the end it mutates into this kind of other thing that is a weird combo of me and Paul’s worst traits into one monster husband that Debbie has to deal with.

Mann: It’s like what I would fantasize about saying to Judd. Debbie can say these things to Pete, but Leslie can’t really say these things to Judd…And it’s fun for [our daughter] Maude: at home we don’t allow her to curse – I know she does at school – so it was fun for her to do that at work. Which I didn’t think was a good idea but Judd thinks is funny. But then she gets home from work and tries to say the F word and we have to shut her down.

Apatow: They use it against me now. “Everybody curses in ‘Superbad!’” She’s finally using it as revenge against me. I knew it’d happen one day. “You make your whole living off of cursing! How can you not like cursing?”

Rudd: There are certain aspects of marriage, parenthood and all of that stuff that seems relatable. We’ve spent years talking about all of this stuff – my wife and I and Leslie and Judd have gotten together, had many dinners and talked. We did that going back to “Knocked Up,” too, so there are aspects of the character that are very much a part of me.

Mann: The only thing that made me feel uncomfortable in this movie is the scene where I’m laying in bed with Iris, because it felt a little invasive. I don’t know why. I can do anything else, but that, for some reason, felt a little like it was crossing some boundary, just because everyone was sitting there watching me with my little girl, doing what I do with my little girl. I didn’t like that.

Rudd: Shooting it, I don’t feel too uncomfortable because it’s the character, but I think I definitely do when it’s all done. Then I’m like, “Oh, wow – that was a little much.” I think I land somewhere in the middle: I don’t have that thing where I’m like “Oh, I can’t watch myself,” and I think I can be critical in good ways. But I don’t do it all that often, once the thing is done. It’s always surreal, the first couple of times.

Mann: I like that uncomfortable tone in a movie. The more uncomfortable, the better. The more truthful, the better. One of my favorite movies of all time is 'Broadcast News,' and I love Albert sitting there sweating while he’s trying to read the news. That’s the greatest thing, ever. It’s so heartbreaking. It’s so uncomfortable to watch, yet so funny. It’s the perfect combination of everything. That’s my dream, to see something like that. That’s fun, to act and to watch.